Process of cleaning a panel in the manufacture of a cathode ray tube

ABSTRACT

A method of for developing a panel in manufacture of a cathode ray tube which prevents possible dispersion of developing liquid to achieve a good developing operation free from irregular development. The method comprises fixing a panel, jetting developing liquid by way of a nozzle toward an inner face of the panel while moving the nozzle in a direction along stripes of a fluorescent face to be formed on the inner face of the panel to perform development of the panel.

This is a continuation of application Ser. No. 07/765,054, filed Sep.24, 1991, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a process of manufacturing a cathode ray tube,and more particularly to a developing method during formation of afluorescent face in manufacture of a cathode ray tube.

2. Description of the Prior Art

In formation of a fluorescent face in manufacture of a color cathode raytube, exposure to light and development, for example, of a PVA(polyvinyl alcohol) photosensitive film, an applied film of carbonslurry or color fluorescent slurry are performed.

A developing operation for an applied film on an inner face of a panelafter an exposure operation is performed by jetting developing liquidtoward an inner face of a panel by way of a nozzle while rotating thepanel.

In such conventional developing operation, since developing liquid isjetted toward a rotating panel by way of a nozzle, such developingliquid is possible dispersed around the panel so that it adheres to aclamping apparatus which clamps the panel thereon or to another panel ata following step and so forth and accordingly has a bad influence onvarious elements around the panel.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a process ofmanufacturing a cathode ray tube which prevents possible dispersion ofdeveloping liquid to achieve a good developing operation free fromirregular development.

In order to attain the object, according to the present invention, thereis provided a method of cleaning a panel in manufacture of a cathode raytube, which comprises the steps of fixing a panel at a predeterminedposition, and jetting developing liquid by way of a nozzle toward aninner face of the panel while moving the nozzle in a direction alongstripes of a fluorescent face to be formed on the inner face of thepanel to perform development of the panel.

With the method, since the nozzle for jetting developing liquid is movedin the direction with a panel held in a fixed condition to performdevelopment of the panel, otherwise possible dispersion of developingliquid around the panel is restricted. Accordingly, a possible badinfluence of such developing liquid to any other element around thepanel can be prevented and a high reliability in the manufacturingprocess can be assured. Further, since the nozzle is moved in thedirection alone stripes of a fluorescent face to be formed in an innerface of the panel, food development free from irregular development canbe achieved. Accordingly, for example, a color fluorescent face of afine pattern can be produced with a high degree of accuracy.

According to another aspect of the present invention, there is providedan apparatus for cleaning a panel in manufacture of a cathode ray tube,which comprises a vessel having an opening at one side thereof, a maskresiliently supported in the vessel and having an opening formedtherein, means for removably mounting a panel in a fixed condition on asubstantially vertical face of the mask adjacent the opening of thevessel in the vessel such that stripes of a fluorescent face to beformed on an inner face of the panel extend in upward and downwarddirections and a seal end face of the panel contacts closely with theface of the mask, a nozzle mounted for movement in the upward anddownward directions adjacent and in parallel to the other face of themask and having a plurality of nozzle elements provided in a horizontalrow thereon in an opposing relationship to the opening of the mask forjetting developing liquid toward the inner face of the panel, and meansfor supplying developing liquid to the nozzle.

With the apparatus, such effects as achieved by the method describedabove can be achieved similarly.

Preferably, the apparatus further comprises a resilient element providedat a location of the mask at which the mask contacts with the seal endface of the panel in order to assure closer contact between the mask andthe seal end face of the panel. The means for removably mountingpreferably includes positioning means for fixing the position of thepanel relative to the mask.

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a developing apparatus for use for a process ofmanufacturing a cathode ray tube according to the present invention:

FIG. 2 is a side elevational view of the developing apparatus of FIG. 1:

FIG. 3 is a vertical sectional view of the developing apparatus of FIG.1: and

FIG. 4 is a perspective view of part of the developing apparatus of FIG.1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to facilitate understanding of the present invention, anexemplary process of forming a color fluorescent face of a color cathoderay tube will be described first, PVP (polyvinyl pyrolidone)photosensitive liquid is poured into an inner face of a panel for acathode ray tube to form a PVP photosensitive film of a uniform filmthickness. Then, after the PVP photosensitive film is dried, it isexposed to light using color selecting electrodes as an optical mask,and then a developing operation is performed by washing of the innerface of the panel with water to form resist layers in the form ofstripes at locations corresponding to individual colors. Subsequently,carbon slurry is poured to the entire inner face of the panel includingthe resist layers to form a uniform applied film of carbon. Then, afterthe applied carbon film Is dried, a reversing agent such as, forexample, hydrogen peroxide is poured into the panel to dissolve theresist layers, and then reversal development is performed by washing ofthe inner face of the panel with water (that is, to lift off the resistlayers together with the applied carbon films thereon) to form carbonstripes, that is, black stripes of s predetermined pattern.Subsequently, PVA (polyvinyl alcohol) photosensitive liquid is pouredinto the panel to form a PVA photosensitive film of a uniform filmthickness, and then, after the PVA photosensitive film is dried,exposure to light corresponding to two colors of, for example, red andblue is performed using the color selecting electrodes as an opticalmask. Then, a developing operation is performed by washing with water toform resist layers at portions corresponding to the two colors of redand blue. After then, slurry of a fluorescent substance of green isapplied, and after such slurry is dried, outer face exposure isperformed from forwardly of a front face of the panel. Then, a reversingagent such as, for example, hydrogen peroxide is poured into the panelto dissolve the resist layers, and then reversal development isperformed by washing with water (that is, to lift off the resist layerstogether with the applied fluorescent slurry films thereon) to formstripes of the green fluorescent substance at positions betweenpredetermined ones of the carbon stripes. After then, stripes of a redfluorescent substance and stripes of a blue fluorescent substance aresuccessively formed in a similar manner at locations between otherrespective predetermined ones of the carbon strips. Subsequently, warmwater is poured into the panel to raise the temperature of the panel,and then an intermediate film (primal) is formed, whereafter a metalback of aluminum is formed, thereby obtaining an object colorfluorescent face.

A developing method in manufacture of a cathode ray tube according tothe present invention can be applied to a developing operation bywashing with water of a PVP photosensitive film or a PVA photosensitivefilm at such fluorescent face forming process as described above andalso to a reversal developing operation by washing with water of anapplied carbon slurry film or an applied fluorescent substance slurryfilm.

In the following, an embodiment of a developing method according to thepresent invention will be described in connection with a developingapparatus shown in FIGS. 1 to 3.

Referring to FIGS. 1 to 3, the developing apparatus shown is generallydenoted at 1 and includes a nozzle 8 for jetting water as developingliquid toward an inner face of a panel 2 fixed in position on thedeveloping apparatus 1, a mask 4 which is contacted, upon development,closely with a seal end face of such panel 2 (that is, a frit seal faceto be joined to a funnel). and a vessel 5 which surrounds, upondevelopment, the entire panel 2.

The nozzle 3 includes a plurality of nozzle elements 3a disposed in twohorizontal rows along leftward and rightward directions of the panel 2,that is, in a direction perpendicular to stripes of a fluorescent faceover the leftward and rightward width of the panel 2. The nozzle 3 isdisposed for movement in upward and downward directions of the panel 2(in directions of the stripes of the fluorescent face) along a guideshaft 15 secured in the vessel 5.

Here, the nozzle 3 includes a plurality of, eight in the presentembodiment, units of such nozzle elements 3a, and eight water supplyports 6 for supplying water to the nozzle 3 therethrough are providedcorresponding to the eight units of the nozzle elements 3a.

The mask 4 has a flat face portion 8 having an area sufficiently greaterthan an area defined by the four sides of the panel 2 (so as to allow anend portion of the panel 2 to approach an inner wall of the vessel 5).The flat face portion 8 of the mask 4 has an opening 7 formed at thecenter thereof corresponding to an opening of the panel 2 and is adaptedto closely contact with a seal end face 2a of the panel 2. The mask 4further has a tubular portion 9 extending from an outer periphery of theflat face portion 8 remotely from the panel 2, A resilient tubularmember 10 is provided at a location of the fiat face portion 8 of themask 4 at which the mask 4 closely contacts with the seal end face 2a ofthe panel 2 in order to improve such close contact between the mask 4and the seal end face 2a of the panel 2, The flat face portion 8 of themask 4 has a positioning portion 11 provided integrally thereon forengaging an outer periphery of the panel 2, The mask 4 is supported inthe vessel 5 by way of springs 12 and 13, The two springs 12 areprovided to bear the weight of the mask 4 while the four springs 13 areprovided at the four corners of the mask 4 to keep the mask 4 in abalanced condition. The nozzle 3 is disposed in the tubular portion 9 ofthe mask 4.

The vessel 5 has an opening 16 into which a panel 2 is to be inserted,and is disposed for movement along a pair of guide rails 18 which areprovided in an inclined condition at a predetermined angle (at 15degrees in the arrangement shown) on a base 17. The vessel 5 is moved byan air cylinder 19.

The developing method of the present embodiment proceeds in thefollowing manner using the apparatus 1 described above.

First, a panel 2 after undergoing an exposure step is clamped by aclamping head of a panel clamping apparatus not shown and fixed at sucha predetermined position as shown in FIG. 2 wherein an inner facethereof is directed obliquely downwardly and stripes to be developed mayextend in upward and downward directions.

Then, the vessel B is advanced from a standby position indicated by asolid line in FIG. 2 to an operative position indicated by a chain linetoward the thus fixed panel 2 by the air cylinder 19 to put the panel 2into the vessel 5. At the chain line position of the vessel 5, a sealend face 2a of the panel 2 is resiliently contacted closely with themask 4 supported on the springs 12 and 13 in the vessel 5 as shown inFIG. 3 while an outer periphery of the panel 2 is engaged with thepositioning portion 11 of the mask 4 thereby to fix the position of themask 4. In this condition, since the vessel 5 is inclined by 15 degreesby the guide rails 18, the nozzle 3 is opposed to an inner face of theinclined panel 2 such that they extend parallel to each other. Then,water as developing liquid is jetted all at once from the nozzleelements 3a of the nozzle 3 while the nozzle 3 is moved in the upwardand downward directions along the guide shaft 15, that is, in thedirections of elongate strip regions allocated on the inner face 4stripes 21 to be developed on the inner face of the panel 2 as shown inFIG. 4 to perform a developing operation.

According to the embodiment described above, since the panel 2 is fixedand the nozzle 3 is moved toward the panel 2 together with the vessel 5and then the nozzle 3 is moved In the directions of the stripes 21 to bedeveloped to perform development, otherwise possible outward dispersionof water as developing liquid is restricted. Then, particularly sincedevelopment is performed while the panel 2 is put in the vessel 5 andthe seal end face 2a of the panel 2 is held in close contact with themask 4, developing liquid is not dispersed to the outside, andconsequently, otherwise possible dispersion of developing liquid aroundthe panel 2 can be prevented with certainty. Accordingly, it can beprevented that developing liquid adheres to the panel clamping apparatusor to another panel at a following step and so forth, and thereliability of the manufacturing process is improved.

Further, since development is performed while moving the nozzle 3 in thelongitudinal directions of the stripes 21, a good developing operationfree from irregular development can be achieved. Accordingly, afluorescent face of such a fine pattern as that on, for example, a highquality color cathode ray tube can be produced with a high degree ofaccuracy.

It is to be noted that the developing apparatus 1 described above can beused for cathode ray tubes of different types having different sizes byexchanging the mask 4.

Having now fully described the invention, it will be apparent to one ofordinary skill in the art that many changes and modifications, can bemade thereto without departing from the spirit and scope of theinvention as set forth herein.

What is claimed is:
 1. A method of cleaning a panel in the manufactureof a cathode ray tube, a cathode ray tube of the type having a pluralityof parallel color stripes of a fluorescent face formed on the inner faceof the panel, comprising the steps of fixing a panel at a position, andjetting developing liquid by way of a nozzle toward an inner face of thepanel while moving said nozzle in a direction corresponding to elongatestrip regions allocated on the inner face for stripes of a fluorescentface to be formed on the inner face of the panel, to perform developmentof the panel.
 2. The method according to claim 1, wherein the step ofjetting developed liquid is further characterized in that a plurality ofnozzles are provided for simultaneously jetting developing liquid ontothe parallel strip regions allocated on the inner face of the panelwhile moving the plurality of nozzles in a direction along the parallelstrip regions.
 3. The method according to claim 2, wherein said step ofjetting developing liquid is further characterized in that saiddeveloping liquid comprises water.
 4. A method of cleaning an inner faceof a cathode ray tube panel in the manufacture of a cathode ray tube,the cathode ray tube of the type having a plurality of parallel colorstripes of a fluorescent face formed on the inner face of the panel,comprising the steps of:holding the panel in a frame; providing a supplyof water and a plurality of nozzles flow connected to the supply ofwater; arranging the nozzles in a spaced environment corresponding toelongate strip regions allocated for parallel, spaced apart colorstripes to be developed on the inner front face of the panel; jettingwater from said nozzles against the inner face of the panel; andtranslating nozzles with respect to the panel along the longitudinaldirection of said strip regions.
 5. The method of claim 4 comprising thefurther steps of before jetting the water from said nozzles, pouring PVPphotosensitive liquid onto the inner face of the panel to form a PVPphotosensitive film of a uniform film thickness; andafter the PVPphotosensitive film is dried, exposing the film to a light using colorselecting electrodes as an optical mask.
 6. The method of claim 5comprising the further steps of:after jetting water from said nozzlesagainst the inner face of the panel, pouring carbon slurry over theentire inner face of the panel to form a uniform applied film of carbon;after the applied carbon film is dried, pouring a reversing agent intothe panel; and using said nozzles and repeating said translating of thenozzles in a longitudinal direction of the strip regions washing theinner face of the panel with water.
 7. The method of claim 6 comprisingthe further steps of;pouring PVA photosensitive liquid into the panel toform a PVA photosensitive film of a uniform film thickness; and afterthe PVA photosensitive film is dried, exposing the panel to light,corresponding to two colors of red and blue using the color selectingelectrodes as an optical mask; and washing the panel with water usingthe nozzles and repeating said translating of the nozzles in alongitudinal direction of the strip regions, to form resist layers atportions corresponding to the two colors of red and blue.
 8. The methodof claim 7 comprising the further steps of:applying a slurry of afluorescent substance of green to the inside surface of the panel; afterthe slurry of the fluorescent substance is dried, exposing the panelfrom a front of the panel; pouring a reversing agent into the panel todissolve the resist layer; and washing the panel with water using thenozzles and repeating said translating of the nozzles in a longitudinaldirection of the stripes to lift off the resist layers together with theapplied fluorescent slurry films thereon to form stripes of the greenfluorescent substance at positions between carbon stripes.